Ethylene copolymer and aromatic vinyl graft copolymer and method for producing the same

ABSTRACT

The present invention provides resin materials endowed with excellent heat resistance, solvent resistance, tensile elongation, toughness, and transparency. Specifically, there are provided an ethylene copolymer having a vinyl group attributed to a diene monomer in the molecular chain and comprising an aromatic vinyl monomer (A), ethylene (B) and a diene monomer (C), and an aromatic vinyl graft copolymer which is a graft copolymerization product of an aromatic vinyl monomer (H) and an ethylene copolymer macromer (I).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an ethylene copolymer and anaromatic vinyl graft copolymer and a method for producing the same. Moreparticularly, the present invention relates to a novel ethylenecopolymer which has a vinyl group in the molecular chain, which isendowed with excellent toughness and compatibility as well as heatresistance and chemical resistance, and which is useful as aheat-resistant elastomer and a raw material of a composite material; toa syndiotactic aromatic vinyl copolymer containing a macromer formed ofthe ethylene copolymer (hereinafter may be simply referred to asethylene copolymer macromer) as a graft component; and to a method forproducing the same effectively.

[0003] 2. Related Art

[0004] Previously, the present inventors successfully developed astyrene polymer having a high syndiotacticity (Japanese PatentApplication Laid-Open (kokai) Nos. 62-10818 and 63-241009). The styrenepolymer having a syndiotactic structure is endowed with excellent heatresistance and chemical resistance, but does not exhibit sufficienttoughness or elongation. In addition, it has poor compatibility withother resins; therefore its use has inevitably been limited.

[0005] In order to overcome this drawback, the present inventorssucceeded in endowing the aforementioned styrene polymer having asyndiotactic structure with toughness by copolymerizing styrene with anolefin (Japanese Patent Application Laid-Open (kokai) Nos. 3-7705,4-130114, and 4-300904).

[0006] However, these polymers are not necessarily satisfactory in termsof toughness, elongation, and compatibility with other resins. Moreover,they sometimes suffer from deterioration of heat resistance. Therefore,there has been demand for a technique which further improves propertiessuch as toughness which maintaining excellent heat resistance.

[0007] Furthermore, there has been demand for a technique to effectivelyimprove toughness and elongation of fragile resins having high glasstransition temperature such as typical polystyrene as well aspolystyrene having a syndiotactic structure.

[0008] The thus-obtained random or block copolymer of styrene and anolefin suffers insufficient controllability of the copolymerizationcomposition as well as a low copolymerization-modification ratio (i.e.,percentage of modifier olefins in the resultant copolymer), leading toinsufficient improvement in toughness, elongation, and compatibilitywith other resins.

[0009] There have also been proposed graft copolymers in which a styrenemonomer is graft-copolymerized with a polymer having double bonds inside chains, as well as block copolymers in which a styrene monomer isblock-copolymerized with a macromonomer having polymerization-activeterminal vinyl groups (Japanese Patent Application Laid-Open (kokai)Nos. 05-247147 and 05-295056). However, the copolymers disclosed in theabove publications exhibit an insufficient graft ratio, resulting ininsufficient improvement in physical properties thereof.

[0010] In view of the foregoing, the present invention is directed tothe provision of an ethylene copolymer which is remarkably useful as amacromonomer for obtaining a syndiotactic polystyrene graft copolymerhaving improved toughness, elongation, etc. or as a material forobtaining a compatibility-enhancing agent for a composition containingsyndiotactic polystyrene and a rubber component, or a composition oftypical polystyrene and a rubber component; the provision of asyndiotactic aromatic vinyl graft copolymer which is endowed withexcellent toughness, elongation, and compatibility as well as heatresistance and chemical resistance, and is useful for a heat-resistantelastomer and a raw material of composite materials; and the provisionof a method for producing the same in an effective manner.

SUMMARY OF THE INVENTION

[0011] The present inventors carried out extensive studies, and as aresult, found that introduction of a styrenic vinyl group into theethylene chain may provide an effective comonomer for obtaining apolystyrene graft copolymer, and that the polystyrene graft copolymermay serve as a compatibility-enhancing agent for a compositioncontaining polystyrene and a rubber component.

[0012] The present inventors also found that a graft copolymer which isobtained from an aromatic vinyl monomer and the aforementioned ethylenecopolymer serving as a macromer and which contains anaromatic-vinyl-monomer-derived chain having a stereospecificity ofhighly syndiotactic structure is endowed with excellent toughness,elongation, and compatibility as well as heat resistance and chemicalresistance.

[0013] Furthermore, the present inventors found that ethylene copolymersare effectively obtained by using a specific catalyst. The presentinvention was accomplished based on these findings.

[0014] Specifically, the present invention provides:

[0015] (1) an ethylene copolymer comprising an aromatic vinyl monomer(A), ethylene (B), and a diene monomer (C) and having in the molecularchain a vinyl group attributed to a diene monomer, wherein recurrentunits attributed to aromatic vinyl monomer (A) is 1-98 mol %, recurrentunits attributed to ethylene (B) is 1-98 mol %, and recurrent unitsattributed to diene monomer (C) is 0.001-10 mol %.

[0016] (2) an ethylene copolymer comprising an aromatic vinyl monomer(A), ethylene (B), a diene monomer (C), and α-olefin (D), and having inthe molecular chain a vinyl group attributed to a diene monomer, whereinrecurrent units attributed to aromatic vinyl monomer (A) is 1-98 mol %,recurrent units attributed to ethylene (B) is 1-98 mol %, recurrentunits attributed to diene monomer (C) is 0.001-10 mol % and recurrentunits attributed to α-olefin (D) is 0-90 mol % (exclusive of 0).

[0017] (3) the ethylene copolymer described in either one of theabove-described (1) or (2), wherein the diene monomer (C) is a dienehaving a styrenic vinyl group.

[0018] (4) a method for producing an ethylene copolymer recited ineither one of the above-described (1) through (3), wherein therespective monomers are copolymerized through use of a catalyst formedof the following components (E) and (F):

[0019] (E) a transition metal compound; and

[0020] (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

[0021] wherein, each of R¹ through R⁵, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group; each ofY¹through Y³ which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

[0022] wherein, each of R⁶ and R⁷, which may be identical to ordifferent from each other, represents a C1-C8 alkyl group; Y⁴ and Y⁵,which may be identical to or different from each other, represents aGroup 13 element; and c and d independently represent numbers between 0and 50 inclusive, with the proviso that c+d is equal to or greater than1: and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).

[0023] (5) a method for producing an ethylene copolymer recited ineither one of the above-described (1) through (3), wherein therespective monomers are copolymerized through use of a catalyst formedof the following components (E), (F) and (G):

[0024] (E) a transition metal compound;

[0025] (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

[0026] wherein, each of R¹ through R⁵, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group; each of Y¹through Y³, which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

[0027] wherein, each of R⁶ and R⁷, which may be identical to ordifferent from each other, represents a C1-C8 alkyl group; Y⁴ and Y⁵,which may be identical to or different from each other, represents aGroup 13 element; and c and d independently represent numbers between 0and 50 inclusive, with the proviso that c+d is equal to or greater than1: and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E): and

[0028] (G) an alkylating agent.

[0029] (6) a method for producing an ethylene copolymer recited ineither one of the above-described (1) through (3), wherein thetransition metal compound (E) is represented by the following formula(3):

[0030] wherein M¹ represents titanium, zirconium, or hafnium; Cp★represents a cyclopentadienyl group or a substituted cyclopentadienylgroup which is bonded to M¹ via a η⁵ bonding mode, an indenyl group, asubstituted indenyl group, a fluorenyl group, a substituted fluorenylgroup, a hexahydroazulenyl group, a substituted hexahydroazulenyl group,a tetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.

[0031] (7) An aromatic vinyl graft copolymer which is a graftcopolymerization product of an aromatic vinyl monomer (H) and ethylenecopolymer macromer (I) and which has in the molecular chain a vinylgroup attributed to a diene monomer; the ethylene copolymer (I) beingobtained through copolymerization of an aromatic vinyl monomer (A),ethylene (B) and a diene monomer (C), wherein recurrent units attributedto aromatic vinyl monomer (A) is 1-98 mol %, recurrent units attributedto ethylene (B) is 1-98 mol %, and recurrent units attributed to dienemonomer (C) is 0.001-10 mol %.

[0032] (8) an aromatic vinyl graft copolymer which is a graftcopolymerization product of an aromatic vinyl monomer (H) and ethylenecopolymer macromer (I) and which has in the molecular chain a vinylgroup attributed to a diene monomer; the ethylene copolymer (I) beingobtained through copolymerization of an aromatic vinyl monomer (A),ethylene (B), a diene monomer (C) and α-olefin (D), wherein recurrentunits attributed to aromatic vinyl monomer (A) is 1-98 mol %, recurrentunits attributed to ethylene (B) is 1-98 mol %, recurrent unitsattributed to diene monomer (C) is 0.001-10 mol % and recurrent unitsattributed to α-olefin (D) is 0-90 mol % (exclusive of 0).

[0033] (9) an aromatic vinyl graft copolymer described in either one ofthe above-described (7) or (8), wherein the diene monomer (C) is a dienehaving a styrenic vinyl group.

[0034] (10) an aromatic vinyl graft copolymer described in either one ofthe above-described (7) through (9), wherein a chain attributed toaromatic vinyl monomer (A) has a stereospecificity of highlysyndiotactic structure.

[0035] (11) an aromatic vinyl graft copolymer described in either one ofthe above-described (7) through (10), wherein the ethylene copolymermacromer (I) is prepared by use of a catalyst formed of the followingcomponents (E) and (F):

[0036] (E) a transition metal compound;

[0037] (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

[0038] wherein, each of R¹ through R⁵, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group; each of Y¹through Y³, which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

[0039] wherein, each of R⁶ and R⁷, which may be identical to ordifferent from each other, represents a C1-C8 alkyl group; Y⁴ and Y⁵,which may be identical to or different from each other, represents aGroup 13 element; and c and d independently represent numbers between 0and 50 inclusive, with the proviso that c+d is equal to or greater than1; and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).

[0040] (12) An aromatic vinyl graft copolymer described in either one ofthe above-described (7) or (10), wherein the ethylene copolymer macromer(I) is prepared by use of a catalyst formed of the following components(E), (F) and (G):

[0041] (E) a transition metal compound;

[0042] (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

[0043] wherein, each of R¹ through R⁵, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group; each of Y¹through Y³, which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

[0044] wherein, each of R⁶ and R⁷, which may be identical to ordifferent from each other, represents a C1-C8 alkyl group; Y⁴ and Y⁵,which may be identical to or different from each other, represents aGroup 13 element; and c and d independently represent numbers between 0and 50 inclusive, with the proviso that c+d is equal to or greater than1; and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E):

[0045] (G) an alkylating agent.

[0046] (13) the method for producing an ethylene copolymer described ineither one of the above-described (9) or (12), wherein the transitionmetal compound (E) is represented by the following formula (3):

[0047] wherein M¹ represents titanium, zirconium, or hafnium; Cp★represents a cyclopentadienyl group or a substituted cyclopentadienylgroup which is bonded to M¹ via a η⁵ bonding mode, an indenyl group, asubstituted indenyl group, a fluorenyl group, a substituted fluorenylgroup, a hexahydroazulenyl group, a substituted hexahydroazulenyl group,a tetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y6 represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.

[0048] (14) the method for producing an aromatic vinyl graft copolymerrecited in either one of the above-described (9) or (13), whereinaromatic vinyl monomer (H) is graft-copolymerized with ethylenecopolymer macromer (I) through use of a catalyst formed of the followingcomponents (E) and (F):

[0049] (E) a transition metal compound; and

[0050] (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

[0051] wherein, each of R¹ through R⁵, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group; each of Y¹through Y³ which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

[0052] wherein, each of R⁶ and R⁷, which may be identical to ordifferent from each other, represents a C1-C8 alkyl group; Y⁴ and Y⁵,which may be identical to or different from each other, represents aGroup 13 element; and c and d independently represent numbers between 0and 50 inclusive, with the proviso that c+d is equal to or greater than1: and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).

[0053] (15) the method for producing an aromatic vinyl graft copolymerdescribed in the above-described (14), wherein the transition metalcompound (E) is represented by the following formula (16) or (17):

M¹⁰R²⁶ _(u)R²⁷ _(v)R²⁸ _(w)R²⁹ _(4−(u+v+w))   (16)

M¹¹R³⁰ _(x)R³¹ _(y)R³² _(3−(x+y))   (17)

[0054] wherein each of M¹⁰ and M¹¹ represents a metal that belongs toGroups 3-6 or the lanthanum group; each of R²⁶ through R³² represents analkyl group, an alkoxy group, an aryl group, an alkylaryl group, anarylalkyl group, an aryloxy group, an acyloxy group, a cyclopentadienylgroup, an alkylthio group, an arylthio group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group,fluorenyl group, an amino group, an amide group, an acyloxy group, aphosphide group, a halogen atom, or a chelating agent; R²⁶ through R²⁹,or R³⁰ through R³² may be identical to or different from each other andtwo of R²⁶ through R²⁹ or R³⁰ through R³² may be cross-linked by use ofCH₂ or Si(CH₃)₂ to form a complex; each of u, v, and w is an integerbetween 0 and 4 inclusive; each of x and y is an integer of 0 and 3inclusive.

[0055] (16) The method for producing an aromatic vinyl graft copolymerdescribed in the above-described (14), wherein the transition metalcompound (E) is represented by the following formula (18):

TiR³³X¹⁴Y¹⁰Z²   (18)

[0056] wherein R³³ represents a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group,or a fluorenyl group, and each of x¹⁴, Y¹⁰, and Z² represents a hydrogenatom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group,alkylaryl group, arylalkyl group, C6-C20 aryloxy group, C1-C20 acyloxygroup, C1-C50 amino group, amide group, phosphide group, alkyl thiogroup, arylthio group, or a halogen atom: compounds in which one of X¹⁴,Y¹⁰, and Z² and R³³ are cross-linked with CH₂, SiR₂, etc.

[0057] (16) the method for producing an aromatic vinyl graft copolymerdescribed in the above-described (14), wherein the transition metalcompound (E) is represented by the following formula (19):

[0058] wherein each of R³⁴ and R³⁵ represents a halogen atom, C1-c20alkoxy group, or an acyloxy group; and z is a number between 2 and 20inclusive.

[0059] (18) the method for producing an aromatic vinyl graft copolymerdescribed in the above-described (14), wherein the transition metalcompound (E) is represented by the following formula (20):

M¹²R³⁶R³⁷R³⁸R³⁹   (20)

[0060] wherein M¹² represents titanium, zirconium, or hafnium; each ofR³⁶ and R³⁷, which may be identical to or different from each other,represents a cyclopentadienyl group, a substituted cyclopentadienylgroup, an indenyl group, or a fluorenyl group; and each of R³⁸ and R³⁹,which may be identical to or different from each other, represents ahydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a C1-C20alkoxy group, an amino group, or a C1-C20 thioalkoxy group, wherein R³⁸and R³⁹ may be cross-linked by the mediation of a C1-C5 hydrocarbongroup, a C1-C20 alkylsilyl group having 1-5 silicon atoms, or a C1-C20germanium-containing hydrocarbon group having 1-5 germanium atoms.

[0061] (19) the method for producing an aromatic vinyl graft copolymeraccording to claims 20, wherein the transition metal compound (E) isrepresented by the following formula (3):

[0062] wherein M¹ represents titanium, zirconium, or hafnium; Cp★represents a cyclopentadienyl group or a substituted cyclopentadienylgroup which is bonded to M¹ via a η⁵ bonding mode, an indenyl group, asubstituted indenyl group, a fluorenyl group, a substituted fluorenylgroup, a hexahydroazulenyl group, a substituted hexahydroazulenyl group,a tetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.

[0063] (20) the method for producing an aromatic vinyl graft copolymerdescribed in either one of the above-described (14) to (19), wherein thecatalyst further contains an alkylating agent (G).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] Embodiments of the present invention will next be described.

[0065] 1. Ethylene copolymer

[0066] The ethylene copolymer according to the present invention is acopolymer comprising an aromatic vinyl monomer (A), ethylene (B), adiene monomer (C), and an optional α-olefin (D) and having in themolecular chain of the copolymer a vinyl group attributed to a dienemonomer.

[0067] (1) Aromatic vinyl monomer (A)

[0068] The aromatic vinyl monomers of formula (A) are compoundsrepresented by the following formula (4):

[0069] wherein X² represents a member which falls within the followingcases 1)-3): 1) a hydrogen atom, 2) a halogen atom, 3) a substituentwhich contains at least one species selected from among a carbon atom, atin atom, or a silicon atom; f represents an integer between 1 and 5inclusive, wherein when f>2, X² may be identical to or different fromone another. Specifically, mention may be given of styrene;alkylstyrenes such as p-methylstyrene, m-methylstyrene, o-methylstyrene,2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene,3,5-dimethylstyrene, p-ethylstyrene, m-ethylstryrene, andp-tert-butylstyrene; halogenated styrenes such as p-chlorostyrene,m-chlorostyrene, o-chlorostyrene, p-bromostyrene, m-bromostyrene,o-bromostyrene, p-fluorostyrene, m-fluorostyrene, o-fluorostyrene, ando-methyl-p-fluorostyrene; alkoxystyrenes such as methoxystyrene,ethoxystyrene, and t-butoxystyrene; vinylbiphenyls;vinylphenylnaphthalenes; vinylphenylanthracenes; halovinylbiphenyls;trialkylsilylvinylbiphenyls; halogen-substituted alkylstyrenes;alkylsilylstyrenes; phenyl-group-containing silylstyrenes;halosilylstyrenes; and silyl-group-containing silylstyrenes. Mixtures oftwo or more of these members are also usable. In addition,vinylnaphthalenes, vinylanthracenes, and their substituents may also beused.

[0070] (2) Ethylene (B)

[0071] No particular limitation is imposed, and a hydrogen may besubstituted by a halogen, etc.

[0072] (3) Diene monomer (C)

[0073] As used herein, the diene monomer (C) is a monomer having two ormore C=C double bonds in the molecule. Mention may be given of C4-C20conjugated diene compounds such as butadiene, isoprene, chloroprene,1,3-hexadiene, 1,3-heptadiene; cyclodiene compounds such ascyclopentadiene, 2,5-norbornadiene, 1,3-cyclohexadiene,1,4-cyclohexadiene, 1,3-cyclooctadiene, and 1,5-cyclooctadiene; andcycloolefins such as vinylnorbornene. Preferably, vinylstyrene compoundshaving styrene vinyl groups, such as those represented by the followingformula (5) and (6), are used.

[0074] wherein each of X³ through X⁵ represents an aromatic compoundresidue such as benzene, naphthalene, or anthracene; an aromaticcompound residue substituted by a C1-C20 alkyl group, such as toluene,xylene, or ethyl benzene; or a halogen-substituted aromatic compoundresidue such as chlorobenzene or bromobenzene; X⁴ and x⁵ may beidentical to or different from one another; each of Y⁷ and Y⁸ representsCH₂, an alkylene group, or an alkyledene group; each of g and hrepresents an integer between 0 and 20 inclusive.

[0075] Specific examples of the compounds represented by formula (5)include o-divinylbenzene, m-divinylbenzene, p-divinylbenezene, (o-, m-,p-)divinyltoluene, (o-, m-, p-)2-propenylstyrene, (o-, m-,p-)3-butenylstyrene, and (o-, m-, p-)4-pentenylstyrene. Examples of thecompounds represented by formula (6) include the compounds describedbelow.

[0076] (4) α-Olefins (D)

[0077] α-Olefins (D) which are usable in the present invention are thoseother than ethylene. Specific examples include α-olefins such aspropylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1,decene-1, 4-phenylbutene-1, 6-phenylhexene-1, 3-methylbutene-1,4-methylpentene-1, 3-methylpentene-1, 3-methylhexene-1,4-methylhexene-1, 5-methylhexene-1, 3,3-dimethylpentene-1,3,4-dimethylpentene-1, 4,4-dimethylpentene-1, and vinylcyclohexane;halogen-substituted α-olefins such as hexafluoropropene,tetrafluoroethylene, 2-fluoropropene, fluoroethylene,1,1-difluoroethylene, 3-fluoropropene, trifluoroethylene, and3,4-dichlorobutene-1; and cycloolefins such as cyclopentene,cyclohexene, norbornene, 5-methylnorbornene, 5-ethylnorbornene,5-propylnorbornene, 5,6-dimethylnorbornene, 1-methylnorbornene,7-methylnorbornene, 5,5,6-trimethylnorbornene, 5-phenylnorbornene; and5-benzylnorbornene. One, two or more of the above-listed compounds maybe used in the present invention.

[0078] (5) The ethylene copolymers (b) are obtained throughcopolymerization of the above-listed monomers.

[0079] In the ethylene copolymers, recurrent units derived from aromaticvinyl monomer (A) are contained in an amount of 1-98 mol %, preferably3-50 mol %, more preferably 5-35 mol %; recurrent units derived fromethylene (B) are contained in an amount of 1-98 mol %, more preferably50-97 mol %, and more preferably 65-95 mol %; and recurrent unitsderived from diene monomer (C) are contained in an amount of 0.001-10mol %, preferably 0.01-5 mol %, more preferably 0.05-3 mol %. In thecase in which α-olefins (D) are optionally used as monomers, recurrentunits derived from α-olefin (D) are in amounts of 0-90 mol % (exclusiveof 0), preferably 0-50 mol % (exclusive of 0), more preferably 0-30 mol% (exclusive of 0). If the amount of the recurrent units attributed toaromatic vinyl monomer (A) is in excess of 98 mol %, brittleness of thecopolymer itself of the present invention increases, whereas thecorresponding amount is less than 1 mol %, compatibility with aromaticvinyl resins may deteriorate, leading to poor grafting ability upon useas a macromonomer. If the amount of the recurrent units attributed toethylene (B) is less than 1 mol %, brittleness of the copolymer itselfincreases, whereas the corresponding amount is in excess of 98 mol %,crystallinity is excessively high, and solubility upon graftcopolymerization may decrease. If the amount of the recurrent unitsattributed to diene monomer (C) is less than 0.001 mol %, graftingability upon use as a macromonomer is insufficient, whereas thecorresponding amount is in excess of 10 mol %, crosslinking reaction mayoccur. In addition, if the amount of the recurrent units attributed toα-olefin (D) is in excess of 90 mol %, crystallinity is excessivelyhigh, and solubility upon graft copolymerization may decrease.

[0080] The limiting viscosity [η] of the ethylene copolymers (b) is0.01-15 dl/g, preferably 0.1-12 dl/g, more preferably 0.5-10 dl/g, asmeasured in decalin at 135° C. In the case in which the limitingviscosity is less than 0.01 dl/g, poor compatibility results when graftcopolymerization is carried out, whereas in the case in which thelimiting viscosity is in excess of 15 dl/g, solubility upon graftpolymerization may become poor. The molecular weight distribution of theethylene copolymers as measured by GPC (gel permeation chromatography)is 8 or less, preferably 6 or less, more preferably 4 or less. If themolecular weight distribution is in excess of 8, graft copolymerizationmay not be carried out efficiently, and in addition, physicochemicalproperties of the resultant graft copolymers may become lowered.

[0081] 2. Methods for producing ethylene copolymers

[0082] Methods for producing the ethylene copolymers of the presentinvention are not particularly limited. For example, in order to producethe ethylene copolymers (b), it is preferable to use a catalyst systemformed of a combination of vanadium halide or titanium halide such asvanadium tetrachloride, vanadium oxytrichloride or titaniumtetrachloride, or vanadium compounds such astri(acetylacetonate)vanadium, tri(2-methyl-1,3-butanedionato)vanadium,or tri(1,3-butanedionato)vanadium; and organic aluminum compounds suchas trialkylaluminum or dialkylaluminum monohalide.

[0083] Alternatively and preferably, the ethylene copolymers may beprepared through copolymerization by use of a catalyst formed of thefollowing (E), (F), and (G). (E): a transition metal compound, (F): anoxygen-containing compound (i) and/or a compound capable of forming anionic complex through reaction with transition metal compound (E) (ii),and (G): an optional alkylation agent.

[0084] (1) Respective components of the catalyst

[0085] (a) Transition metal compounds (E):

[0086] Various transition metal compounds may be used as the transitionmetal compound (E) . Usually, it is preferable to use the compoundsshown below.

[0087] (i) Compounds of formula (3):

[0088] wherein M¹ represents titanium, zirconium, or hafnium; Cp★represents a cyclopentadienyl group or a substituted cyclopentadienylgroup which is bonded to M¹ via a η⁵ bonding mode, an indenyl group, asubstituted indenyl group, a fluorenyl group, a substituted fluorenylgroup, a hexahydroazulenyl group, a substituted hexahydroazulenyl group,a tetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.

[0089] In the present description, examples of the substitutedcyclopentadienyl group include cyclopentadienyl groups substituted withone or more C1-C6 alkyl groups such as a methylcyclopentadienyl group, a1,2-dimethylcyclopentadienyl group, a 1,2,4-trimethylcyclopentadienylgroup, a 1,2,3,4-tetramethylcyclopentadienyl group, atrimethylsilylcyclopentadienyl group, a 1,3-di(trimethylsilyl)cyclopentadienyl group, a tertiary butylcyclopentadienylgroup, a 1,3-di(tertiary butyl)cyclopentadienyl group, a C1-C20hydrocarbyl group, or a C1-C20 halohydrocarbyl group. Examples of thesubstituted indenyl group include a methylindenyl group, adimethylindenyl group, a tetramethylindenyl group, and ahexamethylindenyl group. Examples of the substituted tetrahydroindenylgroup include a 4,5,6,7-tetrahydroindenyl group, a1-methyl-4,5,6,7-tetrahydroindenyl group, a2-methyl-4,5,6,7-tetrahydroindenyl group, a1,2-dimethyl-4,5,6,7-tetrahydroindenyl group, a1,3-dimethyl-4,5,6,7-tetrahydroindenyl group, a1,2,3-trimethyl-4,5,6,7-tetrahydroindenyl group, a1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyl group, a1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyl group, a1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyl group, and a4,5,6,7-tetrahydro-1,2,3-trimethylindenyl group. Examples of thesubstituted fluorenyl group include a methylfluorenyl group, adimethylfluorenyl group, a tetramethylfluorenyl group, and anoctamethylfluorenyl group. Examples of the substitutedtetrahydrofluorenyl group include a 1,2,3,4-tetrahydrofluorenyl groupand a 9-methyl-1,2,3,4-tetrahydrofluorenyl group, and examples of thesubstituted octahydrofluorenyl group include a9-methyl-octahydrofluorenyl group. Examples of the substitutedhexahydroazulenyl group include a 1-methylhexahydroazulenyl group, a2-methylhexahydroazulenyl group, a 1,2-dimethylhexahydroazulenyl group,a 1,3-dimethylhexahydroazulenyl group, and a1,2,3-trimethylhexahydroazulenyl group.

[0090] X¹ represents a σ ligand, and examples include hydrido, halogen,alkyl, silyl, aryl, arylsilyl, amido, aryloxy, alkoxy, silyloxy,phosphido, sulfido, acyl, cyanido, azido, acetylacetonato, and acombination thereof.

[0091] Specific examples of compounds having the above ligands include(t-butylamido) (tetramethylcyclopentadienyl)-1,2-ethanediylzirconiumdichloride,(t-butylamido)-(tetramethylcyclopentadienyl)-1,2-ethanediyltitaniumdichloride,(methylamido)(tetramethylcyclopentadienyl)-1,2-ethanediylzirconiumdichloride,(methylamido)-(tetramethylcyclopentadienyl)-1,2-ethanediyltitaniumdichloride, (ethylamido)(tetramethylcyclopentadienyl)-methylenetitaniumdichloride,(t-butylamido)dimethyl-(tetramethylcyclopentadienyl)silanetitaniumdichloride,(t-butylamido)dimethyl(tetramethylcyclopentadienyl)-silanezirconiumdichloride,(t-butylamido)dimethyl-(tetramethyl-cyclopentadienyl)-silanetitaniumdimethyl,(t-butylamido)dimethyl-(tetramethyl-cyclopentadienyl)silanezircon iumdimethyl,(t-butylamido)dimethyl-(tetramethylcyclopentadienyl)-silanetitaniumdibenzyl,(t-butylamido)dimethyl-(tetramethylcyclopentadienyl)-silanezirconiumdibenzyl,(benzylamido)dimethyl-(tetramethylcyclopentadienyl)silanetitaniumdichloride,(phenylphosphido)dimethyl-(tetramethylcyclopentadienyl)-silanezirconiumdibenzyl,(t-butylamido)dimethyl-(tetramethylcyclopentadienyl)silanetitaniumchloride, (dimethylaminoethyl)tetramethylcyclopentadienyl-titanium(III)dichloride, 9-(dimethylaminoethyl)octahydro-fluorenyltitanium(III)dichloride,(di-n-butylaminoethyl)tetramethyl-cyclopentadienyltitanium(III)dichloride,(dimethylaminomethyl)tetramethyl-cyclopentadienyltitanium(III)dichloride, and(dimethylaminopropyl)tetramethylcyclopentadienyl-titanium(III)dichloride.

[0092] (ii) Compounds represented by the following formula (7):

[0093] wherein M² represents a transition metal of Group 4 in theperiodic table; Cp represents a cyclopentadienyl skeleton; Y⁹ representsO, S, NR, PR, CR₂, or a neutral two-electron donor selected from OR, SR,NR₂, and PR₂; B represents an atom of Group 14 in the periodic table; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;each of X⁶ and X⁷, which may be identical to or different from eachother, represents a hydrogen atom, a halogen atom, a C1-C20 hydrocarbylgroup, a C1-C20 halohydrocarbyl group, a C1-C20 alkoxy group, a C6-C20aryloxy group, or a C2-C20 di-substituted amino group; and each of R⁸through R¹³, which may be identical to or different from one another andmay be arbitrarily linked to form a ring, represents a hydrogen atom, ahalogen atom, a C1-C20 hydrocarbyl group, a C1-C20 halohydrocarbylgroup, a C1-C20 alkoxy group, a C6-C20 aryloxy group, a C2-C20di-substituted amino group, or a C1-C20 silyl group.

[0094] The groups having a cyclopentadienyl skeleton in the above Cprepresent a group such as a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group, afluorenyl group, a substituted fluorenyl group, a hexahydroazulenylgroup, a substituted hexahydroazulenyl group, a tetrahydroindenyl group,a substituted tetrahydroindenyl group, a tetrahydrofluorenyl group, asubstituted tetrahydrofluorenyl group, a octahydrofluorenyl group, or asubstituted octahydrofluorenyl group. Examples of B include a carbonatom, a silicon atom, and a germanium atom, with a carbon atom and asilicon atom being preferred.

[0095] Specific examples of the compounds represented by formula (7)includeisopropylidene(cyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(methylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(dimethylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(trimethylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(tetramethylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride, isopropylidene(n-propylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titanium dichloride, isopropylidene(primary butylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(phenylcyclopentadienyl)(3-t-butyl-5-methyl-2-phenoxy)titaniumdichloride,isopropylidene(cyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride,isopropylidene(methylcyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride,isopropylidene(dimethylcyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride,isopropylidene(trimethylcyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride,isopropylidene(tetramethylcyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride, isopropylidene(n-propylcyclopentadienyl)(3-t-butyl-2-phenoxy)titanium dichloride, isopropylidene(primarybutylcyclopentadienyl)(3-t-butyl-2-phenoxy)titanium dichloride,isopropylidene(phenylcyclopentadienyl)(3-t-butyl-2-phenoxy)titaniumdichloride, isopropylidene(cyclopentadienyl)(2-phenoxy)titaniumdichloride, isopropylidene(methylcyclopentadienyl)(2-phenoxy)titaniumdichloride, isopropylidene(dimethylcyclopentadienyl)(2-phenoxy)titaniumdichloride, isopropylidene(trimethylcyclopentadienyl)(2-phenoxy)titaniumdichloride,isopropylidene(tetramethylcyclopentadienyl)(2-phenoxy)titaniumdichloride, isopropylidene(n-propylcyclopentadienyl) (2-phenoxy)titaniumdichloride, isopropylidene(primarybutylcyclopentadienyl)(2-phenoxy)titanium dichloride, andisopropylidene(phenylcyclopentadienyl)(2-phenoxy)titanium dichloride.Examples also include the above compounds in which titanium issubstituted with zirconium or hafnium and in which isopropylidene issubstituted with dimethylsilylene, diphenylsilylene, or methylene.Examples further include the above compounds in which dichloride issubstituted with dibromide, diiodide, dimethyl, dibenzyl, dimethoxide,or diethoxide.

[0096] (iii) Compounds represented by the following formula (8) or (9):

[0097] wherein each of E¹ through E⁴ represents a substituted orunsubstituted cyclopentadienyl group, an indenyl group, or a fluorenylgroup, a substituted fluorenyl group; each of A¹ and A² represents ahydrogen atom, a C1-C10 alkyl group, a C6-C20 aryl group, a C6-C20alkylaryl group, a C6-C20 arylalkyl group, a C6-C20 haloaryl group, or aC1-C20 hydrocarbon group containing a hetero atom which is selected fromamong oxygen, nitrogen, sulfur, and silicon; Q, which connects E¹ andE², represents a C2-C10 hydrocarbon group, a C1-C10 hydrocarbon groupcontaining silicon, germanium, or tin, a carbon atom, a silicon atom, agermanium atom, or a tin atom; A¹ and A² may be linked to each other toform a ring together with Q; each of R¹⁴ through R¹⁷ represents ahalogen atom, a hydrogen atom, a C1-C10 alkyl group, asilicon-containing alkyl group, a C6-C20 aryl group, a C6-C20 alkylarylgroup, or a C6-C20 arylalkyl group; each of M³ and M⁴ representstitanium, zirconium, or hafnium.

[0098] Specific examples of E¹ through E⁴ mentioned above include acyclopentadienyl group, a methylcyclopentadienyl group, adimethylcyclopentadienyl group, a tetramethyl-cyclopentadienyl group, anindenyl group, a 3-methylindenyl group, a tetrahydroindenyl group, afluorenyl group, a methylfluorenyl group, and a 2,7-di-t-butylfluorenylgroup.

[0099] Specific examples of A¹ and A² include a hydrogen atom, a methylgroup, an ethyl group, a propyl group, a phenyl group, a toluyl group, afluorophenyl group, a methoxyphenyl group, and a benzyl group.

[0100] In the case in which A¹ and A² are linked to each other and forma ring structure together with Q, specific examples of groups which maybe formed by A¹, A², and Q include a cyclopentylidene group, acyclohexylidene group, and a tetrahydropyran-4-ylidene group.

[0101] Preferable examples of R¹⁴ through R¹⁷ include a chlorine atom, amethyl group, a phenyl group, and a trimethylsilylmethyl group.

[0102] Specific examples of the above-mentioned transition metalcompounds include ethylenebis(1-indenyl)zirconium dichloride,ethylenebis(tetrahydro-1-indenyl)zirconium dichloride,isopropylidene(cyclopentadienyl)-(fluorenyl)zirconium dichloride,methylphenylmethylene-(cyclopentadienyl) (fluorenyl)zirconiumdichloride, and diphenylmethylene(cyclopentadienyl)(fluorenyl)zirconiumdichloride.

[0103] (iv) Transition metal compounds having a single π ligand R¹⁶represented by the following formula (10):

M⁵R¹⁸X⁸ _(i)   (10)

[0104] wherein M⁵ represents a transition metal of Group 4 in theperiodic table or a lanthanide metal; R¹⁸ represents a π ligand, e.g., agroup having a cyclopentadienyl skeleton; X⁸ represents a hydrogen atom,a halogen atom, a C1-C20 hydrocarbyl group, a C1-C20 alkoxy group, aC1-C20 thioalkoxy group, a C6-C20 aryl group, a C6-C20 aryloxy group, aC6-C20 thioaryloxy group, an amino group, or an alkylsilyl group; aplurality of X⁸ may be identical to or different from one another andmay be linked to R¹⁸ via a specific group; and i represents the valenceof M⁵.

[0105] Examples of the compounds represented by formula (9) includemono(cyclopentadienyl)transition metal compounds,mono(indenyl)transition metal compounds, and mono(fluorenyl)transitionmetal compounds. Examples of the substituted cyclopentadienyl groupinclude cyclopentadienyl groups substituted with one or more C1-C6 alkylgroups such as a methylcyclopentadienyl group, a1,3-dimethylcyclopentadienyl group, a 1,2,4-trimethylcyclopentadienylgroup, a 1,2,3,4-tetramethylcyclopentadienyl group, atrimethylsilylcyclopentadienyl group, a 1,3-di (trimethylsilyl)cyclopentadienyl group, a tertiary butylcyclopentadienyl group, a1,3-di(tertiary butyl)cyclopentadienyl group, and apentamethylcyclopentadienyl group. Titanium is preferably used as atransition metal. Examples of the titanium compounds includecyclopentadienyltrimethyltitanium, cyclopentadienyltriethyltitanium,cyclopentadienyltripropyltitanium, cyclopentadienyltributyltitanium,methylcyclopentadienyltrimethyltitanium,1,2-dimethylcyclopentadienyltrimethyltitanium1,2,4-trimethylcyclopentadienyltrimethyltitanium,1,2,3,4-tetramethylcyclopentadienyltrimethyltitanium,pentamethylcyclopentadienyltrimethyltitanium,pentamethylcyclopentadienyltriethyltitanium,pentamethylcyclopentadienyltripropyltitanium,pentamethylcyclopentadienyltributyltitanium,cyclopentadienylmethyltitanium dichloride, cyclopentadienylethyltitaniumdichloride, pentamethylcyclopentadienylmethyltitanium dichloride,pentamethylcyclopentadienylethyltitanium dichloride,cyclopentadienyldimethyltitanium monochloride,cyclopentadienyldiethyltitanium monochloride, cyclopentadienyltitaniumtrimethoxide, cyclopentadienyltitanium triethoxide,cyclopentadienyltitanium tripropoxide, cyclopentadienyltitaniumtriphenoxide, pentamethylcyclopentadienyltitanium trimethoxide,pentamethylcyclopentadienyltitanium triethoxide,pentamethylcyclopentadienyltitanium tripropoxide,pentamethylcyclopentadienyltitanium triphenoxide,cyclopentadienyltitanium trichloride,pentamethylcyclopentadienyltitanium trichloride,cyclopentadienylmethoxytitanium dichloride,cyclopentadienyldimethoxytitanium chloride,pentamethylcyclopentadienylmethoxytitanium dichloride,cyclopentadienyltribenzyltitanium,pentamethylcyclopentadienylmethyldiethoxytitanium, indenyltitaniumtrichloride, indenyltitanium trimethoxide, indenyltitanium triethoxide,indenyltrimethyltitanium, indenyltribenzyltitanium,pentamethylcyclopentadienyltitanium trithiomethoxide,pentamethylcyclopentadienyltitanium trithiophenoxide.

[0106] (b) Oxygen-containing compounds (i) and/or compounds capable offorming an ionic complex through reaction with a transition metalcompound (ii) (F):

[0107] The component (F) which serves as the polymerization catalyst inthe present invention contains the below-described oxygen-containingcompounds (i) and/or compounds capable of forming an ionic complexthrough reaction with a transition metal compound (ii).

[0108] (i) Oxygen-containing compounds

[0109] The oxygen-containing compounds comprise a compound representedby the below-described formula (1):

[0110] and/or a compound represented by the below-described formula (2):

[0111] wherein, each of R¹ through R⁷, which may be identical to ordifferent from one another, represents a C1-C8 alkyl group,specifically, a methyl group, an ethyl group, an n-propyl group, anisopropyl group, a butyl group, a pentyl group, a hexyl group, a heptylgroup, or an octyl group. R¹ to R⁵ may be identical to or different fromone another. Each of R⁶ and R⁷, which may be identical to or differentfrom each other. Each of Y¹ through Y⁵ represents a Group 13 element,specifically, B, Al, Ga, In, and Tl, with B and Al being preferred. Y¹through Y⁵ may be identical to or different from one another, wherein Y¹and Y⁵ may be identical to or different from each other. Each of athrough d is a number between 0 and 50 inclusive, and each of (a+b) and(c+d) is a number of 1 or more. The preferable range for each of athrough d is 1-20 inclusive, with 1-5 inclusive being particularlypreferred.

[0112] Preferable examples of the oxygen-containing compounds used asthe above-mentioned catalyst component, particularly examples ofalkylaluminoxanes, include compounds having a proportion of thehigh-magnetic field component in a methyl proton signal region of 50% orless based on an aluminum-methyl (Al—CH₃) bond measured through a ¹H—NMRspectrum. Briefly, when the above oxygen-containing compound issubjected to measurement of its ¹H—NMR spectrum in a solvent toluene atroom temperature, a methyl proton signal based on Al—CH₃ is observed inthe range between 1.0 and −0.5 ppm with tetramethylsilane (TMS) as astandard. Since the proton signal of TMS (0 ppm) exists in the regionfor observing a methyl proton based on Al—CH₃, a methyl proton signal ismeasured with a methyl proton signal ranging from toluene of 2.35 ppm tothe TMS standard as a standard. The signal is formed of a high-magneticfield component (i.e., from 0.1 to −0.5 ppm) and the other component(i.e., from 1.0 to −0.1 ppm). The compounds which may preferably be usedhave a high-magnetic field component of 50% or less, preferably 45-5%.

[0113] (ii) Compounds capable of forming an ionic complex throughreaction with a transition metal compound

[0114] Examples of the compound capable of forming an ionic complexthrough reaction with a transition metal compound include Lewis acidsand coordination compounds comprising a cation and an anion containing ametal to which a plurality of groups are bonded. There exist a varietyof coordination compounds which comprise a cation and an anioncontaining a metal to which a plurality of groups are bonded, andcompounds represented by the below-described formulas (11) and (13) maypreferably be used:

([L¹−H]^(j+))_(k)([M⁶X⁹X¹⁰. . . X^(n1)]^((n1−n3)−))_(m)   (11)

([L²]^(p+))_(q)([M⁷X¹¹X¹². . . X^(n2)]^((n2−n4)−))_(r)   (12)

[0115] wherein L¹represents a Lewis base, each of M⁶ and M⁷ represents ametal selected from Group 5 to Group 15 elements; L² represents thebelow-mentioned M^(8,) R¹⁹R²⁰M⁹, or R²¹ ₅C, wherein M⁸ represents ametal of Group 1 or a metal selected from Group 8 to Group 12 elements;M⁹represents a metal selected from Group 8 to Group 10 elements; each ofR¹⁹ and R²⁰ represents a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, or a fluorenyl group; R²¹represents an alkyl group; each of X⁹, X¹⁰ through X^(n1) and X¹¹, X¹²through X^(n2) represents a hydrogen atom, a dialkylamino group, analkoxy group, an aryloxy group, a C1-C20 alkyl group, a C6-C20 arylgroup, an alkylaryl group, an arylalkyl group, a substituted alkylgroup, an organic metalloid group, or a halogen atom; n3 represents avalence of M⁶ and n4 represents a valence of M⁷, and is an integerbetween 1-7 inclusive; each of n1 and n2 is an integer between 2 and 8inclusive; j represents an ion valence of L¹-H and p represents an ionvalence of L², and each of j and p is an integer between 1-7 inclusive;each of k and q is an integer of one or more; m=kxj/(n1-n3); andr=qxp/(n2-n4).

[0116] Examples of M⁶ and M⁷ include atoms such as B, Al, Si, P, As, orSb; examples of M⁸ include atoms such as Ag, Cu, Na, or Li; and examplesof M⁹ include atoms such as Fe, Co, or Ni. Examples of X⁹, X¹⁰ throughX^(n1) and X¹¹, X¹² through X,^(n2) include dialkylamino groups such asa dimethylamino group or a diethylamino group; alkoxy groups such as amethoxy group, an ethoxy group, or an n-butoxy group; aryloxy groupssuch as a phenoxy group, a 2,6-dimethylphenoxy group, or a naphthyloxygroup; C1-C20 alkyl groups such as a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an n-octyl group,or a 2-ethylhexyl group; C6-C20 aryl groups, alkylaryl groups, orarylalkyl groups such as a phenyl group, a p-tolyl group, a benzylgroup, a pentafluorophenyl group, a 3,5-di(trifluoromethyl)phenyl group,a 4-tert-butylphenyl group, a 2,6dimethylphenyl group, a3,5-dimethylphenyl group, a 2,4-dimethylphenyl group, or a1,2-dimethylphenyl group; halogens such as F, Cl, Br, or I; organicmetalloid groups such as a pentamethylantimonyl; a trimethylsilyl, atrimethylgermyl group, a diphenylarsenyl, a dicyclohexylantimonyl, or adiphenylboron group. Examples of the (substituted) cyclopentadienylgroup represented by R¹⁹ and R²⁰, respectively, include amethylcyclopentadienyl group, a butylcyclopentadienyl group, and apentamethylcyclopentadienyl group.

[0117] Specific examples of the anion containing a metal to which aplurality of groups are bonded include B(C₆F₅)₄ ⁻, B(C₆HF₄)₄ ⁻,B(C₆H₂F₃)₄ ⁻, B(C₆H₃F₂)₄ ⁻, B(C₆H₄F)₄ ⁻, B(C₆H₅)₄ ⁻, B(C₆CF₃F₄)₄ ⁻,B(C₆C₂H₅F₄)₄ ⁻, PF₆ ⁻, P(C₆F₅)₆ ⁻, and Al(C₆HF₄)₄ ⁻. Examples of themetal-containing cation include Cp₂Fe⁺, (MeCp)₂Fe⁺, (t-BuCp)₂Fe⁺,(Me₂Cp)₂Fe⁺, (Me₃Cp)₂Fe⁺, (Me₄Cp)₂Fe⁺, (Me₅Cp)₂Fe⁺, Ag⁺, Na⁺, and Li⁺andexamples of the other cations include nitrogen-containing compounds suchas pyridinium, 2,4-dinitro-N,N-diethylanilinium, diphenylammonium,p-nitroanilinium, 2,5-dichloroanilinium, p-nitro-N,N-dimethylanilinium,quinolinium, N,N-dimethylanilinium, or N,N-diethylanilinium; carbeniumcompounds such as triphenylcarbenium, tri(4-methylphenyl)carbenium, ortri(4-methoxyphenyl)carbenium; alkylphosphonium ions such as CH₃PH₃ ⁺,C₂H₅PH₃ ⁺, C₃H₇PH₃ ⁺, (CH₃)₂PH₂ ⁺, (C₂H₅)₂PH₂ ⁺, (C₃H₇)₂PH₂ ⁺,(CH₃)₃PH⁺, (C₂H₅)_(3PH) ⁺,(C₃H₇)₃PH⁺, (CF₃)₃PH⁺, (CH₃)₄P⁺, (C₂H₅)₄P⁺, or(C₃H₇)₄P⁺; and arylphosphonium ions such as C₆H₅PH₃ ⁺, (C₆H₅)₂PH₂ ⁺,(C₆H₅)₃PH³⁰ , (C₆H₅)₄P⁺, (C₂H₅)₂(C₆H₅) PH⁺, (CH₃) (C₆H₅)PH₂ ⁺,(CH₃)₂(C₆H₅)PH⁺, or (C₂H₅)₂(C₆H₅)₂P⁺.

[0118] Specifically, among the compounds represented by formulas (11)and (12), the following compounds are preferably used. Examples of thecompound represented by formula (11) include triethylammoniumtetraphenylborate, tri(n-butyl)ammonium tetraphenylborate,trimethylammnonium tetraphenylborate, triethylammoniumtetrakis(pentafluorophenyl)borate, tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)borate, triethylammonium hexafluoroarsenate,pyridinium tetrakis(pentafluorophenyl)borate, pyrroliniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, and methyldiphenylammoniumtetrakis(pentafluorophenyl)borate. Examples of the compound representedby formula (14) include ferrocenium tetraphenylborate,dimethylferrocenium tetrakis(pentafluorophenyl)borate, ferroceniumtetrakis(pentafluorophenyl)borate, decamethylferroceniumtetrakis(pentafluorophenyl)borate, acetylferroceniumtetrakis(pentafluorophenyl)borate, formylferroceniumtetrakis(pentafluorophenyl)borate, cyanoferrocenium tetrakis(pentafluorophenyl)borate, silver tetraphenylborate, silvertetrakis(pentafluorophenyl)borate, trityl tetraphenylborate, trityltetrakis(pentafluorophenyl)borate, silver hexafluoroarsenate, silverhexafluoroantimonate, and silver tetrafluoroborate.

[0119] Examples of the Lewis acids which may be used include B(C₆F₅)₃,B(C₆HF₄)₃, B(C₆H₂F₃)₃, B(C₆H₃F₂)₃, B(C₆H₄F)₃, B(C₆CF₃F₄)₃, PF₅, andAl(C₆HF₄)₃. In the polymerization catalysts used in the presentinvention as the component (F), oxygen-containing compounds mayexclusively be used singly or in combination of two or more speciesserving as the component (i) or compounds being able to form an ioniccomplex through reaction with a transition metal compound mayexclusively be used singly or in combination of two or more speciesserving as the component (ii). Alternatively, the component (i) and thecomponent (ii) may appropriately used in combination.

[0120] (c) Alkylating agents (G):

[0121] There are a variety of alkylating agents, and examples thereofinclude alkyl group-containing aluminum compounds represented by formula(13):

R²² _(S)Al (OR²³) _(t)X¹³ _(3−S−t)   (13)

[0122] wherein each of R²² and R²³ represents a C1-C8, preferably aC1-C4, alkyl group; X¹³ represents a hydrogen atom or a halogen atom; sis defined as 0<s<3, and is preferably 2 or 3, most preferably 3; t isdefined as 0<t<3, and is preferably 0 or 1; alkyl group-containingmagnesium compounds represented by formula (14):

R²⁴ ₂Mg   (14)

[0123] wherein R²⁴ represents a C1-C8, preferably a C1-C4, alkyl group;and alkyl group-containing zinc compounds represented by formula (15):

R²⁵ ₂Zn   (15)

[0124] wherein R²⁵ represents a C1-C8, preferably a C1-C4, alkyl group.

[0125] Among these alkyl group-containing compounds, alkylgroup-containing aluminum compounds, inter alia, trialkylaluminumcompounds and dialkylaluminum compounds, are preferred.

[0126] (2) Methods for preparing the catalysts

[0127] Examples of methods for contacting components (E) and (F) of thecatalysts for polymerization with an optional component (G) include (1)adding the component (G) to a mixture of the component (E) and thecomponent (F) to thereby provide a catalyst, and contacting monomers tobe polymerized with the catalyst; (2) adding the component (E) to amixture of the component (F) and the component (G) to thereby provide acatalyst, and contacting monomers to be polymerized with the catalyst;(3) adding the component (F) to a mixture of the component (E) and thecomponent (G) to thereby provide a catalyst, and contacting monomers tobe polymerized with the catalyst; (4) individually contacting thecomponents (E), (F), and (G) with monomer components to be polymerized;and (5) contacting a mixture of a monomer component to be polymerizedand the component (G) with the catalysts prepared in the above (1)through (3).

[0128] The above component (E) and component (F) are contacted with theoptional component (G) at the polymerization temperature or in thetemperature range from −20 to 200° C.

[0129] Organic aluminum compounds such as triisobutylaluminum may beadded prior to feeding catalyst components so as to scavenge impurities.

[0130] (3) Polymerization methods

[0131] Bulk polymerization may be employed as the polymerization method,and polymerization may be conducted in aliphatic hydrocarbon solventssuch as pentane, hexane, or heptane; alicyclic hydrocarbon solvents suchas cyclohexane; and aromatic hydrocarbon solvents such as benzene,toluene, xylene, or ethylbenzene. No particular limitation is imposed onthe polymerization temperature, and it is typically 0-200° C.,preferably 20-100° C.

[0132] In the obtained aromatic vinyl graft copolymers, thecompositional ratio of polymer segment derived from aromatic vinylmonomer (H) and that derived from ethylene copolymer macromer (I) can beregulated through feed amounts of the monomers (I).

[0133] 3. Aromatic vinyl graft copolymers

[0134] The aromatic vinyl graft copolymers of the present invention aregraft copolymerization products between an aromatic vinyl monomer (H)and the above-described ethylene copolymer (hereinafter may be referredto as ethylene copolymer macromer) (I). The ethylene copolymer macromer(I) is obtained through copolymerization of aromatic vinyl monomer (A),ethylene (B), and diene monomer (C), wherein the amount of the recurrentunits attributed to aromatic vinyl monomer (A) is 1-98 mol %, the amountof the recurrent units attributed to ethylene (B) is 1-98 mol %, and theamount of the recurrent units attributed to diene monomer (C) is0.001-10 mol %. The molecular chain of the aromatic vinyl graftcopolymer is an ethylene copolymer having a vinyl group attributed to adiene monomer. The chains derived from aromatic vinyl monomers in thepolymer products have stereospecificity of highly syndiotacticstructure.

[0135] (1) Aromatic vinyl monomers (H)

[0136] Specific description of the aromatic vinyl monomers (H) isomitted, since the aromatic vinyl monomers (H) which are usable in thepresent invention are identical to those which are used ascopolymerization components in the preparation of the aforementionedethylene copolymers.

[0137] (2) Ethylene copolymer macromers (I)

[0138] The ethylene copolymer macromers (I) of the present invention areobtained through copolymerization of aromatic vinyl monomer (A),ethylene (B), diene monomer (C), and an optional α-olefin (D), and areidentical to those listed for the aforementioned ethylene copolymers.Therefore, detailed description thereof is omitted.

[0139] The aromatic vinyl graft copolymers of the present invention areobtained through copolymerization of the aforementioned aromatic vinylmonomer (A) and the aforementioned ethylene copolymer macromer (I). Thearomatic vinyl graft copolymers are preferably constituted by 97-50 wt%, more preferably 95-50 wt %, most preferably 90-60 wt %, of thepolymer segment attributed to aromatic vinyl monomer (H), and 3-50 wt %,more preferably 5-50 wt %, most preferably 10-40 wt %, of a polymersegment attributed to the ethylene copolymer (I). The polymer segmentattributed to ethylene copolymer (I) encompasses components both graftedand not grafted. In the case in which the polymer segment attributed toethylene copolymer (I) is present in an amount of less than 3 wt %,satisfactory effect for improving toughness may not be obtained, whereasthe corresponding amount is in excess of 50 wt %, the melt viscosity ofthe graft copolymer will increase, and thus molding may become difficultor the elastic modulus may decrease, to thereby cause deformation duringmold release following molding. The graft ratio (“weight of graftedcomponents among the segments of ethylene copolymer (I)”/“weight ofpolymer segments attributed to ethylene copolymer (I) containing bothgrafted components and non-grafted components”) is prferably 10 wt % ormore, more preferably 20 wt % or more. If the ratio is less than 10 wt%, sufficient effect for improving toughness of the graft copolymer maynot be obtained.

[0140] The limiting viscosity [η] of the aromatic vinyl graft copolymerof the present invention is 0.05-10 dl/g, preferably 0.1-8 dl/g, morepreferably 1-5 dl/g, as measured in decalin at 135° C. If the limitingviscosity is less than 0.05 dl/g, satisfactory compatibility-enhancingeffect may not be exhibited, and thus toughness may not besatisfactorily improved. On the other hand, if the limiting viscosity isin excess of 10 dl/g, the viscosity when the copolymer is meltedextremely increases, to thereby hamper polymerization of the aromaticvinyl monomer to result in a reduced graft efficiency.

[0141] In the aromatic vinyl graft copolymers of the present invention,the chain attributed to an aromatic vinyl monomer has astereospecificity of highly syndiotactic structure; i.e., in the case ofracemic diad, a syndiotacticity of 75% or more, preferably not less than85%, and in the case of racemic pentad, a syndiotacticity of 30% ormore, preferably not less than 50%. When a mixture of two or moremonomers is used as a styrene monomer, the segment derived from thestyrene monomer may be a random or block copolymerization product of themonomers.

[0142] 4. Method for preparing aromatic vinyl graft copolymers

[0143] No particular limitation is imposed on the method for preparingthe aromatic vinyl graft copolymers. For example, they may be obtainedby adding a powdery ethylene copolymer macromer (I) to a syndiotacticaromatic vinyl polymer powder which has already been synthesized andheating to initiate reaction. Preferably, the ethylene copolymermacromer (I) may be obtained by dissolving in an aromatic vinyl monomer(H) or in a solvent containing the monomer (H), then copolymerizing byuse of: (E) a transition metal compound, (H) (i) an oxygen-containingcompound and/or (ii) a compound that can form an ionic complex throughreaction with a transition metal compound (E), and (G) an optionalalkylating agent. In this case, there is preferably used a method inwhich the ethylene copolymer macromer (I) is dissolved in an aromaticvinyl monomer (H) or a solvent containing the same (H), in view ofconducting homogeneous reaction. No particular limitation is imposed onthe solvent, and hydrocarbon solvents such as toluene, benzene, orethylbenzene are preferably used. Next will be described catalystspreferably used for copolymerization.

[0144] (1) Components of catalyst:

[0145] (a) Transition metal compounds (J)

[0146] A variety of transition metals may be used as (a) transitionmetal compound (J), and there may be used the aforementioned transitionmetal compounds serving as the component of the polymerization catalystfor the above-described ethylene copolymer macromer (I). Moreover,compounds represented by formula (16) or formula (17) may be used.

M¹⁰R²⁶ _(u)R²⁷ _(v)R²⁸ _(w)R²⁹ _(4−(u+v+w))   (16)

M¹¹R³⁰ _(x)R³¹ _(y)R³² _(3−(x+y))   (17)

[0147] wherein each of M¹⁰ and M¹¹ represents a metal that belongs toGroups 3-6 or the lanthanum group; each of R²⁶ through R³² represents analkyl group, an alkoxy group, an aryl group, an alkylaryl group, anarylalkyl group, an aryloxy group, an acyloxy group, a cyclopentadienylgroup, an alkylthio group, an arylthio group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group,fluorenyl group, an amino group, an amide group, an acyloxy group, aphosphide group, a halogen atom, or a chelating agent; each of u, v, andw is an integer between 0 and 4 inclusive; each of x and y is an integerof 0 and 3 inclusive; and two of R²⁶ through R²⁹ or two of R³⁰ throughR³² may be cross-linked by use of CH₂ or Si(CH₃)₂ to form a complex.

[0148] Preferably, each of the metal M¹⁰ and M¹¹ that belongs to Groups3-6 or the lanthanum group is a metal that belongs to group 4, interalia, titanium, zirconium, and hafnium. Preferable titanium compoundsare represented by the following formula (18):

T i R³³X¹⁴Y¹⁰Z²   (18)

[0149] wherein R³³ represents a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group,or a fluorenyl group, and each of X¹⁴, Y¹⁰, and Z² represents a hydrogenatom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group,alkylaryl group, arylalkyl group, C6-C20 aryloxy group, C1-C20 acyloxygroup, C1-C50 amino group, amide group, phosphide group, alkyl thiogroup, arylthio group, or a halogen atom. Compounds in which one of X¹⁴,Y¹⁰ and Z², and R³³ are cross-linked with CH₂, SiR₂, etc. also fallwithin the definition of the formula (18) compounds.

[0150] Of these titanium compounds, those having no halogen atom arepreferred. Particularly, titanium compounds having a single π-electronsystem ligand as described above are preferred.

[0151] Also, as titanium compounds, there may be used condensationtitanium compounds represented by the following formula (19):

[0152] wherein each of R³⁴ and R³⁵ represents a halogen atom, C1-C20alkoxy group, or an acyloxy group; and z is a number between 2 and 20inclusive. These titanium compounds may be transformed into complexes byuse of esters or ether before use.

[0153] Examples of other transition metal compounds which serve ascomponent (a) include those having two conjugate-π-electron-containingligands, and specifically, mention may be given of at least one compoundselected from among the transition metal compounds represented by thefollowing formula (20):

M¹²R³⁶R³⁷R³⁸R³⁹   (20)

[0154] wherein M¹² represents titanium, zirconium, or hafnium; each ofR³⁶ and R³⁷ represents a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, or a fluorenyl group; and eachof R³⁸ and R³⁹ represents a hydrogen atom, a halogen atom, a C1-C20hydrocarbon group, a C1-C20 alkoxy group, an amino group, or a C1-C20thioalkoxy group, wherein R³⁶ and R³⁷ may be cross-linked by themediation of a C1-C5 hydrocarbon group, a C1-C20 alkylsilyl group having1-5 silicon atoms, or a C1-C20 germanium-containing hydrocarbon grouphaving 1-5 germanium atoms.

[0155] (b) (i) oxygen-containing compounds and/or (ii) compounds capableof forming an ionic complex through reaction with a transition metalcompound (F):

[0156] Compounds described in relation to the synthesis of ethylenecopolymer macromers may be used.

[0157] (c) Alkylating agents (G):

[0158] Those described in relation to the synthesis of ethylenecopolymer macromers may be used.

[0159] (2) Preparation of catalysts:

[0160] Examples of methods for contacting components (J) and (F) of thecatalysts for polymerization with optional component (G) include thefollowing methods (1) through (5). According to method (1), component(G) is added to a mixture of component (J) and component (F) to therebyprovide a catalyst. The catalyst is contacted with monomers to bepolymerized (i.e., in the present invention, a solution obtained bydissolving macromer (I) in aromatic vinyl monomer (H) or in a solventcontaining aromatic vinyl monomer (H)). According to method (2),component (E) is added to a mixture of component (F) and component (G)to thereby provide a catalyst, and the catalyst is contacted withmonomers to be polymerized. According to method (3), component (F) isadded to a mixture of component (J) and component (G) to thereby providea catalyst, and the catalyst is contacted with monomers to bepolymerized. According to method (4), respective components (J), (F),and (G) are individually contacted with monomer components to bepolymerized. According to method (5), a mixture of a monomer componentto be polymerized and component (G) with a catalyst prepared by any ofthe methods (1) through (3).

[0161] The above component (J) and component (Fb) may be contacted withthe optional component (G) at the polymerization temperature or in thetemperature range of −20 to 200° C.

[0162] The catalysts used in polymerization are thus formed of acombination of the aforementioned components (J) and (F), or of acombination of the aforementioned components (J), (F), and (G). Othercatalyst components may also be incorporated in the catalyst system. Theproportions of respective catalysts may vary in accordance withconditions and thus are not univocally determined. Usually, if thecomponent (F) is an oxygen-containing compound, the mole ratio ofcomponent (J) to component (F) is preferably from 1:1 to 1:10,000, morepreferably from 1:1 to 1:1,000; if the component (F) is a compound whichis capable of forming an ionic complex through reaction with atransition metal compound, the mole ratio of component (J) to component(F) is preferably from 0.1:1 to 1:0.1; and if component (G) is used, themole ratio of component (J) to component (G) is preferably from 1:0.1 to1:1,000.

[0163] Prior to feeding catalyst components, organic aluminum compoundssuch as triisobutylaluminum may be added so as to scavenge impurities.

[0164] (3) Polymerization methods:

[0165] Bulk polymerization may be employed as the polymerization method,and polymerization may be conducted in aliphatic hydrocarbon solventssuch as pentane, hexane, or heptane; alicyclic hydrocarbon solvents suchas cyclohexane; and aromatic hydrocarbon solvents such as benzene,toluene, xylene, or ethylbenzene. No particular limitation is imposed onthe polymerization temperature, and it is typically 0-200° C.,preferably 20-100° C.

[0166] The proportions of the polymer segment derived from aromaticvinyl monomer (H) and that derived from ethylene copolymer macromer (I)in the final aromatic vinyl graft copolymer may be suitably regulated inaccordance with the amounts of aromatic vinyl monomer (H) and macromer(I) which undergo polymerization.

EXAMPLES

[0167] The present invention will next be described in more detail byway of example.

Example 1

[0168] In a 2-liter pressure-proof polymerization tank were placeddehydrated toluene (260 ml), active-alumina-treated purified styrene(600 ml), active-alumina-treated p-divinylbenzene (4.5 ml)(manufacturedby Nippon Steel Chemical Co., Ltd., high-purity para isomer T-30), andmethylaluminoxane (manufactured by Albermer) such that an aluminumconcentration was 9 mmol. Ethylene was fully melted under a constantpressure of 0.6 MPa, and (t-butylamido)dimethyl (η-1,2,3,4-tetrahydro-9-fluorenyl) silanetitanium dichloride was added theretosuch that an titanium concentration was 15 μmol. Subsequently, ethylenewas subjected to polymerization at 70° C. for 30 minutes under aconstant ethylene pressure.

[0169] After removal of ethylene gas, polymerization was terminated byaddition of a small amount of methanol.

[0170] The obtained viscous solution was precipitated in methanol, and apolymer was recovered. The polymer was dried at 50° C. under reducedpressure, to thereby obtain an ethylene copolymer (83.8 g).

[0171] The composition was confirmed by ¹H—NMR to beethylene/styrene/divinylbenzene=78.4/21.5/0.1 (mol %). The amount ofdivinylbenzene was calculated from the NMR peak corresponding to thevinyl groups. Styrenic vinyl groups were confirmed to exist in themolecular chain.

[0172] No cross-linked product in a gel form was produced. The obtainedethylene copolymer had a [η] of 1.3 and a molecular weight distribution(Mw/Mn) of 1.87 as measured by GPC.

Example 2

[0173] The procedure of Example 1 was repeated except that the amount ofdehydrated toluene was 500 ml, the amount of active-alumina-treatedpurified styrene was 930 ml, the amount of active-alumina-treatedp-divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd.,high-purity para isomer T-30) was 10.5 ml, the amount ofmethylaluminoxane (manufactured by Albermer) was such that an aluminumconcentration was 18 mmol, triisobutylaluminoxane (manufactured byTosoh-Akzo Co., Ltd.) was further added thereto such that an aluminumconcentration was 0.5 mmol, the amount of (t-butylamido) dimethyl(η⁵-1,2,3,4-tetrahydro-9-fluorenyl)silanetitanium dichloride was suchthat an titanium concentration was 30 μ mol, and polymerizationtemperature was 90° C.

[0174] An ethylene copolymer was obtained in an amount of 115.3 g.

[0175] The composition was confirmed by ¹H—NMR to beethylene/styrene/divinylbenzene=71.1/28.6/0.4 (mol %). The amount ofdivinylbenzene was calculated from the NMR peak corresponding to thevinyl groups. Styrenic vinyl groups were confirmed to exist in themolecular chain.

[0176] No cross-linked product in a gel form was obtained. The obtainedethylene copolymer had a [η] of 1.4 and a molecular weight distribution(Mw/Mn) of 1.89 as measured by GPC.

Example 3

[0177] The procedure of Example 1 was repeated except that the capacityof the pressure-proof container was 1 liter; no toluene was used;active-alumina-treated purified styrene (200 ml), active-alumina-treatedp-divinylbenzene (1.5 ml)(manufactured by Nippon Steel Chemical Co.,Ltd., high-purity para isomer T-30), and methylaluminoxane (manufacturedby Albermer) (in the concentration as reduced to the aluminumconcentration of 5.0 mmol) were added; a mixture gas of ethylene andpropylene (8:2 by mol ratio) was then continuously added thereto untilethylene and propylene were fully dissolved and the pressure in thecontainer reached a steady state at 0.6 MPa; and (t-butylamido) dimethyl(η⁵-1,2,3,4-tetrahydro-9-fluorenyl)silanetitanium dichloride was addedthereto such that a titanium concentration was 5 μmol, to thereby obtainan ethylene-propylene copolymer (15.2 g).

[0178] The composition was confirmed by ¹H—NMR to beethylene/propylene/styrene/divinylbenzene=68.5/12.2/19.1/0.3 (mol %).The amount of divinylbenzene was calculated from the NMR peakcorresponding to the vinyl groups. Styrenic vinyl groups were confirmedto exist in the molecular chain.

[0179] No cross-linked product in a gel form was produced. The obtainedethylene copolymer had a [η] of 1.2 and a molecular weight distribution(Mw/Mn) of 1.51 as measured by GPC.

Example 4

[0180] (1) Synthesis of ethylene copolymer macromer

[0181] In a 2-liter pressure-proof polymerization tank were placeddehydrated toluene (500 ml), active-alumina-treated purified styrene(1000 ml), active-alumina-treated divinylbenzene (5.0 ml)(manufacturedby Nippon Steel Chemical Co., Ltd., high-purity para and meta isomerT-30, divinylbenzene content: 70 wt.%), and methylaluminoxane(manufactured by Albermer) such that an aluminum concentration was 18mmol. Ethylene was fully melted under a constant pressure of 0.8 MPa,and (t-butylamido)dimethyl(tetramethyl-η⁵cyclopentadienyl)silanetitaniumdichloride was added thereto such that a titanium concentration was 30μmol. Subsequently, ethylene was subjected to polymerization at 70° C.for 90 minutes under a constant ethylene pressure. After removal ofethylene gas, polymerization was terminated by addition of a smallamount of methanol.

[0182] The resultant viscous solution was precipitated in methanol, anda polymer was recovered. The polymer was dried at 50° C. under reducedpressure, to thereby obtain an ethylene copolymer (115 g).

[0183] The composition was confirmed by ¹H—NMR to beethylene/styrene/divinylbenzene=71.3/28.5/0.2 (mol %). The limitingviscosity [η] was 1.4.

[0184] (2) Synthesis of aromatic vinyl graft copolymer

[0185] In a 500-ml separable flask were placed fully-dehydrated toluene(150 ml) and active-alumina-treated purified styrene (100 ml). Afterpurge with nitrogen, the ethylene copolymer macromer (6.0 g) synthesizedin procedure (1) above was added to the mixture under stirring. Themacromer was completely dissolved in the styrene monomer liquid at 50°C.

[0186] Next, the solution of ethylene copolymer macromer in styrene washeated to 75° C., and triisobutyl aluminum (1.0 mmol) was added thereto.Subsequently, a titanium-mixed catalyst prepared in advance was addedthereto such that a titanium concentration was 5.0 μmol, and the mixturewas subjected to polymerization for 10 minutes under stirring. Themixture ratio of the titanium-mixed catalyst wasmethylaluminoxane:triisobutyl aluminum:titanium=75:25:1 (mol ratio), andthe titanium was in the form of1,2,3,4,5,6,7,8-octahydrofluorenyltitanium trimethoxide.

[0187] Polymerization was terminated by addition of a small amount ofmethanol. The polymer was washed with methanol and dried at 50° C. underreduced pressure for 12 hours, to thereby obtain a polymer (yield: 17.1g).

[0188] The thus-obtained aromatic vinyl graft copolymer had a totalethylene copolymer macromer content of 35 wt. %. The ethylene copolymermacromer had a limiting viscosity [η] of 1.4 dl/g. The graft ratio was37.1 wt.%, and the tensile elongation was 95%.

Example 5

[0189] The procedure of Example 4 was repeated except that, in step (2),the amount of toluene was 400 ml, the amount of ethylene copolymermacromer was 12.0 g, the amount of titanium-mixed catalyst was such thata titanium concentration was 15.0 μmol, to thereby obtain a polymer(yield: 44.4 g).

[0190] The thus-obtained aromatic vinyl graft copolymer had a totalethylene copolymer macromer content of 27 wt. %. The ethylene copolymermacromer had a limiting viscosity [η] of 1.4 dl/g. The graft ratio was62.8 wt. %, and the tensile elongation was 94%.

Example 6

[0191] (1) Synthesis of ethylene copolymer macromer

[0192] In a 2-liter pressure-proof polymerization tank were placeddehydrated toluene (500 ml), active-alumina-treated purified styrene(1000 ml), active-alumina-treated divinylbenzene (5.0 ml)(manufacturedby Nippon Steel Chemical Co., Ltd., high-purity para and meta isomerT-30, divinylbenzene content: 70 wt. %), and methylaluminoxane(manufactured by Albermer) such that an aluminum concentration was 25mmol. Subsequently, a mixture gas of ethylene and propylene (8:2 by molratio) was continuously added thereto until ethylene and propylene werefully dissolved and the pressure in the container reached a steady stateat 0.6 Mpa, and(t-butylamido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanetitaniumdichloride was then added thereto such that a titanium concentration was30 μmol, followed by polymerization at 70° C. for 90 minutes under aconstant ethylene pressure. After removal of ethylene gas,polymerization was terminated by addition of a small amount of methanol.

[0193] The thus-obtained viscous solution was precipitated in methanol,and a polymer was recovered. The polymer was dried at 50° C. underreduced pressure, to thereby obtain an ethylene copolymer (108 g).

[0194] The composition was confirmed by ¹H—NMR to beethylene/propylene/styrene/divinylbenzene=57.8/13.8/28.2/0.2 (mol %).The limiting viscosity [η] was 1.2.

[0195] (2) Synthesis of aromatic vinyl graft copolymer

[0196] The procedure of Example 5 was repeated except that ethylenecopolymer macromer obtained in step (1) above was used in an amount of12 g. The yield of the polymer was 35.8 g.

[0197] The thus-obtained aromatic vinyl graft copolymer had a totalethylene copolymer macromer content of 34 wt. %. The ethylene copolymermacromer had a limiting viscosity [η] of 1.2 dl/g. The graft ratio was61.5 wt. %, and the tensile elongation was 88%.

Comparative Example 1

[0198] (1) Synthesis of ethylene copolymer macromer having no vinylgroups

[0199] The procedure of Example 4 was repeated except thatp-divinylbenzene was not used in step (1), to thereby synthesize anethylene copolymer macromer having no vinyl groups.

[0200] The amount of the obtained ethylene copolymer was 125 g, and thecomposition was confirmed to beethylene/styrene/divinylbenzene=73.6/26.4/0 (mol %). The limitingviscosity [η] was 1.5.

[0201] (2) Synthesis of aromatic vinyl graft copolymer

[0202] The procedure of Example 4 was repeated except that ethylenecopolymer macromer obtained in the step (1) above was used instead. Theyield of the polymer was 15.9 g.

[0203] The thus-obtained product had a total ethylene copolymer macromercontent of 25 wt. %. The ethylene copolymer macromer had a limitingviscosity [η] of 1.5 dl/g. The graft ratio was 0 wt. %, and the tensileelongation was 6%.

Comparative Example 2

[0204] Polystyrene having a homo-type syndiotactic structure(Mw=200,000) and SEBS (G1651; manufactured by Shell Chemical Co., Ltd.)were mixed at a weight ratio of 80:20, and the mixture was pelletized at300° C. by use of a biaxial extruder (30 mmØ; manufactured by IkegaiSteelwork Co., Ltd.)

[0205] The thus-obtained product had an SEBS content of 20 wt. %. Thegraft ratio was 0 wt. %, and the tensile elongation was 13%.

[0206] The respective evaluation items for the above aromatic vinylgraft copolymer were measured as follows:

[0207] (1) Ethylene copolymer macromer content (wt. %)

[0208] This is represented by % by weight of ethylene copolymer macromercontained in the aromatic vinyl graft copolymer, and obtained throughthe following equation: amount of incorporated ethylene copolymermacromer/amount of final polymer.

[0209] (2) Graft ratio (wt. %)

[0210] This is represented by the following expression: “weight ofgrafted components among the segments of ethylene copolymer (I)”/“weightof copolymer segments attributed to ethylene copolymer (I) containingboth grafted components and non-grafted components.” Specifically,“weight of grafted components among the segments of ethylene copolymer(I)” represents the value of the total weight of ethylene copolymermacromer minus the weight of non-grafted ethylene copolymer macromer,and “weight of copolymer segments attributed to ethylene copolymer (I)containing both grafted components and non-grafted components”represents the total weight of the ethylene copolymer macromer obtainedin step (1) above. The amount of non-grafted components is the weight ofethylene copolymer which is recovered from a methylene chloride phaseobtained by subjecting a fine dry powder of the graft copolymer to a 6hrSoxhlet extraction in methylene chloride.

[0211] (3) Tensile elongation (%)

[0212] A pellet of aromatic vinyl graft copolymer was heated to 300° C.and shaped into a press sheet having a thickness of 100 μm, followed byannealing at 200° C. for 30 minutes so as to fully crystallize.Subsequently, dumbbell-shaped test pieces were punched out and subjectedto a tensile elongation test.

[0213] The tensile elongation test was performed by use of a SHIMADZUAUTOGRAPH AG5000B. The dumbbell type was DIN-53504. The tensile rate was1.0 mm/sec, and the initial length was 20 mm.

[0214] As described above, the ethylene copolymers obtained by thepresent invention are endowed with excellent heat resistance, chemicalresistance, etc., as well as with remarkable toughness, elongation, andcompatibility. Therefore, they are very useful in the followingapplications among others: macromonomers for obtaining syndiotacticpolystyrene graft copolymers which are advantageously used as a rawmaterial for complex materials or heat-resistant elastomers; andcompatibility-enhancing agents for a composition containing asyndiotactic polystyrene and a rubber component or a compositioncontaining typical polystyrene and a rubber component.

What is claimed is:
 1. An ethylene copolymer comprising an aromaticvinyl monomer (A), ethylene (B) and a diene monomer (C), and having inthe molecular chain a vinyl group attributed to a diene monomer, whereinrecurrent units attributed to aromatic vinyl monomer (A) is 1-98 mol %,recurrent units attributed to ethylene (B) is 1-98 mol % and recurrentunits attributed to diene monomer (C) is 0.001-10 mol %.
 2. An ethylenecopolymer comprising an aromatic vinyl monomer (A), ethylene (B), adiene monomer (C), and α-olefin (D), and having in the molecular chain avinyl group attributed to a diene monomer, wherein recurrent unitsattributed to aromatic vinyl monomer (A) is 1-98 mol %, recurrent unitsattributed to ethylene (B) is 1-98 mol %, recurrent units attributed todiene monomer (C) is 0.001-10 mol % and recurrent units attributed toα-olefin (D) is 0-90 mol % (exclusive of 0).
 3. The ethylene copolymeraccording to claim 1, wherein the diene monomer (C) is a diene having astyrenic vinyl group.
 4. The ethylene copolymer according to claim 2,wherein the diene monomer (C) is a diene having a styrenic vinyl group.5. A method for producing an ethylene copolymer recited in claim 1,wherein the respective monomers are copolymerized through use of acatalyst formed of the following components (E) and (F): (E) atransition metal compound; and (F) an oxygen-containing compound (i)represented by the following formula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 6. A method for producingan ethylene copolymer recited in claim 2, wherein the respectivemonomers are copolymerized through use of a catalyst formed of thefollowing components (E) and (F): (E) a transition metal compound; and(F) an oxygen-containing compound (i) represented by the followingformula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y3,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 7. A method for producingan ethylene copolymer recited in claim 3, wherein the respectivemonomers are copolymerized through use of a catalyst formed of thefollowing components (E) and (F): (E) a transition metal compound; and(F) an oxygen-containing compound (i) represented by the followingformula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y4 and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 8. A method for producingan ethylene copolymer recited in claim 4, wherein the respectivemonomers are copolymerized through use of a catalyst formed of thefollowing components (E) and (F): (E) a transition metal compound; and(F) an oxygen-containing compound (i) represented by the followingformula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 9. A method for producingan ethylene copolymer recited in claim 1, wherein the respectivemonomers are copolymerized through use of a catalyst formed of thefollowing components (E) and (F): (E) a transition metal compound; and(F) an oxygen-containing compound represented by the following formula(1):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y3,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greaterthan
 1. 10. A method for producing an ethylene copolymer recited inclaim 1, wherein the respective monomers are copolymerized through useof a catalyst formed of the following components (E) and (F): (E) atransition metal compound; and (F) an oxygen-containing compoundrepresented by the following formula (2):

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than
 1. 11.A method for producing an ethylene copolymer recited in claim 1, whereinthe respective monomers are copolymerized through use of a catalystformed of the following components (E) and (F): (E) a transition metalcompound; and (F) a compound capable of forming an ionic complex throughreaction with transition metal compound (E).
 12. A method for producingan ethylene copolymer recited in claim 1, wherein the respectivemonomers are copolymerized through use of a catalyst formed of thefollowing components (E), (F) and (G): (E) a transition metal compound;(F) an oxygen-containing compound (i) represented by the followingformula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³,which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E): and (G) an alkylatingagent.
 13. A method for producing an ethylene copolymer recited in claim1, wherein the respective monomers are copolymerized through use of acatalyst formed of the following components (E), (F) and (G): (E) atransition metal compound; (F) an oxygen-containing compound representedby the following formula (1):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1: and (G) an alkylating agent.
 14. A method for producing an ethylenecopolymer recited in claim 1, wherein the respective monomers arecopolymerized through use of a catalyst formed of the followingcomponents (E), (F) and (G): (E) a transition metal compound; (F) anoxygen-containing compound represented by the following formula (2):

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1: and(G) an alkylating agent.
 15. A method for producing an ethylenecopolymer recited in claim 1, wherein the respective monomers arecopolymerized through use of a catalyst formed of the followingcomponents (E), (F) and (G): (E) a transition metal compound; (F) acompound capable of forming an ionic complex through reaction withtransition metal compound (E): and (G) an alkylating agent.
 16. Themethod for producing an ethylene copolymer according to claim 5, whereinthe transition metal compound (E) is represented by the followingformula (3):

wherein M¹ represents titanium, zirconium, or hafnium; Cp★ represents acyclopentadienyl group or a substituted cyclopentadienyl group which isbonded to M¹ via a η⁵ bonding mode, an indenyl group, a substitutedindenyl group, a fluorenyl group, a substituted fluorenyl group, ahexahydroazulenyl group, a substituted hexahydroazulenyl group, atetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.
 17. An aromatic vinyl graft copolymer whichis a graft copolymerization product of an aromatic vinyl monomer (H) andethylene copolymer macromer (I) which has in the molecular chain a vinylgroup attributed to a diene monomer; the ethylene copolymer (I) beingobtained through copolymerization of an aromatic vinyl monomer (A),ethylene (B) and a diene monomer (C), wherein recurrent units attributedto aromatic vinyl monomer (A) is 1-98 mol %, recurrent units attributedto ethylene (B) is 1-98 mol %, and recurrent units attributed to dienemonomer (C) is 0.001-10 mol %.
 18. An aromatic vinyl graft copolymerwhich is a graft copolymerization product of an aromatic vinyl monomer(H) and ethylene copolymer macromer (I) and which has in the molecularchain a vinyl group attributed to a diene monomer; the ethylenecopolymer (I) being obtained through copolymerization of an aromaticvinyl monomer (A), ethylene (B), a diene monomer (C) and α-olefin (D),wherein recurrent units attributed to aromatic vinyl monomer (A) is 1-98mol %, recurrent units attributed to ethylene (B) is 1-98 mol %,recurrent units attributed to diene monomer (C) is 0.001-10 mol % andrecurrent units attributed to α-olefin (D) is 0-90 mol % (exclusive of0).
 19. An aromatic vinyl graft copolymer according to claim 17, whereinthe diene monomer (C) is a diene having a styrenic vinyl group.
 20. Anaromatic vinyl graft copolymer according to claim 18, wherein the dienemonomer (C) is a diene having a styrenic vinyl group.
 21. An aromaticvinyl graft copolymer according to claim 17, wherein a chain attributedto aromatic vinyl monomer (A) has a stereospecificity of highlysyndiotactic structure.
 22. An aromatic vinyl graft copolymer accordingto claim 17, wherein a chain attributed to aromatic vinyl monomer (A)has a stereospecificity of highly syndiotactic structure.
 23. Anaromatic vinyl graft copolymer according to claim 17, wherein theethylene copolymer macromer (I) is prepared by use of a catalyst formedof the following components (E) and (F): (E) a transition metalcompound; (F) an oxygen-containing compound (i) represented by thefollowing formula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1;and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 24. An aromatic vinyl graftcopolymer according to claim 17, wherein the ethylene copolymer macromer(I) is prepared by use of a catalyst formed of the following components(E), (F) and (G): (E) a transition metal compound; (F) anoxygen-containing compound (i) represented by the following formula (1)or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ through Y³which may be identical to or different from one another, represents aGroup 13 element; and a and b independently represent numbers between 0and 50 inclusive, with the proviso that a+b is equal to or greater than1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1;and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E): (G) an alkylating agent.25. The method for producing an ethylene copolymer according to claim23, wherein the transition metal compound (E) is represented by thefollowing formula (3):

wherein M¹ represents titanium, zirconium, or hafnium; Cp★ represents acyclopentadienyl group or a substituted cyclopentadienyl group which isbonded to M¹ via a η⁵ bonding mode, an indenyl group, a substitutedindenyl group, a fluorenyl group, a substituted fluorenyl group, ahexahydroazulenyl group, a substituted hexahydroazulenyl group, atetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.
 26. The method for producing an ethylenecopolymer according to claim 24, wherein the transition metal compound(E) is represented by the following formula (3):

wherein M¹ represents titanium, zirconium, or hafnium; Cp★ represents acyclopentadienyl group or a substituted cyclopentadienyl group which isbonded to M¹ via a η⁵ bonding mode, an indenyl group, a substitutedindenyl group, a fluorenyl group, a substituted fluorenyl group, ahexahydroazulenyl group, a substituted hexahydroazulenyl group, atetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y¹ and Z¹.
 27. The method for producing an aromaticvinyl graft copolymer according to claims 17, wherein aromatic vinylmonomer (H) is graft-copolymerized with ethylene copolymer macromer (I)through use of a catalyst formed of the following components (E) and(F): (E) a transition metal compound; and (F) an oxygen-containingcompound (i) represented by the following formula (1) or (2):

wherein, each of R¹ through R⁵, which may be identical to or differentfrom one another, represents a C1-C8 alkyl group; each of Y¹ throughY^(3,) which may be identical to or different from one another,represents a Group 13 element; and a and b independently representnumbers between 0 and 50 inclusive, with the proviso that a+b is equalto or greater than 1;

wherein, each of R⁶ and R⁷, which may be identical to or different fromeach other, represents a C1-C8 alkyl group; Y⁴ and Y⁵, which may beidentical to or different from each other, represents a Group 13element; and c and d independently represent numbers between 0 and 50inclusive, with the proviso that c+d is equal to or greater than 1:and/or a compound (ii) capable of forming an ionic complex throughreaction with transition metal compound (E).
 28. The method forproducing an aromatic vinyl graft copolymer according to claim 27,wherein the transition metal compound (E) is represented by thefollowing formula (16) or (17): M¹⁰R²⁶ _(u)R²⁷ _(v)R²⁸ _(w)R²⁹_(4−(u+v+w))   (16) M¹¹R³⁰ _(x)R³¹ _(y)R³² _(3−(x+y))   (17) whereineach of M¹⁰ and M¹¹ represents a metal that belongs to Groups 3-6 or thelanthanum group; each of R²⁶ through R³² represents an alkyl group, analkoxy group, an aryl group, an alkylaryl group, an arylalkyl group, anaryloxy group, an acyloxy group, a cyclopentadienyl group, an alkylthiogroup, an arylthio group, a substituted cyclopentadienyl group, anindenyl group, a substituted indenyl group, fluorenyl group, an aminogroup, an amide group, an acyloxy group, a phosphide group, a halogenatom, or a chelating agent; R²⁶ through R²⁹, or R³⁰ through R³² may beidentical to or different from each other; each of u, v, and w is aninteger between 0 and 4 inclusive; each of x and y is an integer of 0and 3 inclusive; and two of R²⁶ through R²⁹ or R³⁰ through R³² may becross-linked by use of CH₂ or Si(CH₃)₂ to form a complex.
 29. The methodfor producing an aromatic vinyl graft copolymer according to claim 27,wherein the transition metal compound (E) is represented by thefollowing formula (18): T i R³³X¹⁴Y¹⁰Z²   (18) wherein R³³ represents acyclopentadienyl group, a substituted cyclopentadienyl group, an indenylgroup, a substituted indenyl group, or a fluorenyl group, and each ofX¹⁴, Y¹⁰, and Z² represents a hydrogen atom, a C1-C20 alkyl group, aC1-C20 alkoxy group, a C6-C20 aryl group, alkylaryl group, arylalkylgroup, C6-C20 aryloxy group, C1-C20 acyloxy group, C1-C50 amino group,amide group, phosphide group, alkyl thio group, arylthio group, or ahalogen atom: compounds in which one of X¹⁴, Y¹⁰, and Z² and R³³ arecross-linked with CH₂, SiR₂, etc..
 30. The method for producing anaromatic vinyl graft copolymer according to claim 27, wherein thetransition metal compound (E) is represented by the following formula(19):

wherein each of R³⁴ and R³⁵ represents a halogen atom, C1-c20 alkoxygroup, or an acyloxy group; and z is a number between 2 and 20inclusive.
 31. The method for producing an aromatic vinyl graftcopolymer according to claim 27, wherein the transition metal compound(E) is represented by the following formula (20): M¹²R³⁶R³⁷R³⁸R³⁹   (20)wherein M¹² represents titanium, zirconium, or hafnium; each of R³⁶ andR³⁷, which may be identical to or different from each other, representsa cyclopentadienyl group, a substituted cyclopentadienyl group, anindenyl group, or a fluorenyl group; and each of R³⁸ and R³⁹, which maybe identical to or different from each other, represents a hydrogenatom, a halogen atom, a C1-C20 hydrocarbon group, a C1-C20 alkoxy group,an amino group, or a C1-C20 thioalkoxy group, wherein R³⁸ and R³⁹ may becross-linked by the mediation of a C1-C5 hydrocarbon group, a C1-C20alkylsilyl group having 1-5 silicon atoms, or a C1-C20germanium-containing hydrocarbon group having 1-5 germanium atoms. 32.The method for producing an aromatic vinyl graft copolymer according toclaim 27, wherein the transition metal compound (E) is represented bythe following formula (3):

wherein M¹ represents titanium, zirconium, or hafnium; Cp★ represents acyclopentadienyl group or a substituted cyclopentadienyl group which isbonded to M¹ via a η⁵ bonding mode, an indenyl group, a substitutedindenyl group, a fluorenyl group, a substituted fluorenyl group, ahexahydroazulenyl group, a substituted hexahydroazulenyl group, atetrahydroindenyl group, a substituted tetrahydroindenyl group, atetrahydrofluorenyl group, a substituted tetrahydrofluorenyl group, anoctahydrofluorenyl group, or a substituted octahydrofluorenyl group; X¹represents a σ ligand; e represents 1 or 2; a plurality of X¹ may beidentical to or different from one another and may be linked togethervia an arbitrary group; Y⁶ represents O, S, NR, PR, CR₂, or a neutraltwo-electron donor selected from OR, SR, NR₂, or PR₂; Z¹ representsSiR₂, CR₂, SiR₂SiR₂, CR₂CR₂, CR=CR, CRSiR₂, GeR₂, BR, or BR₂; Rrepresents hydrogen, an alkyl group, an aryl group, a silyl group, ahaloalkyl group, a haloaryl group, or a combination of at least two ofthe above groups selected so as to have 20 or fewer non-hydrogen atoms;and two or more of the above R may further form a condensed ring systemwith Z¹ or with Y⁶ and Z¹.
 33. The method for producing an aromaticvinyl graft copolymer according to claim 27, wherein the catalystfurther contains an alkylating agent (G).